South Sydney revealed on Wednesday morning that a "minor procedure" will keep him out for between three and four weeks, all but certainly ruling him out of the opening Origin clash against Queensland on June 8 in Sydney.
Despite the fact both Frizell and Sims have struggled for form at the Knights and Dragons respectively - two teams who are both fighting to avoid being in the bottom eight - Fittler told The Sydney Morning Herald that he knew what both players would bring to the side.
“Tariq played all three games for us last year, and I just like what he’s about,” Fittler told the publication.
“He’s not too old. I’m old. He’s always done a job for us. It’s the same with Tyson. Players always look better in better teams, but I know what he’s about.”
It's anticipated that Liam Martin will move into the starting team to cover for the role Murray is vacating after he lined up on the edge last year, with Isaah Yeo to once again hold the Blues' number 13 jersey.
Martin's second-row partner is up for dispute though, and the fact both Sims and Frizell are well in calculations only adds to the situation.
Keaon Koloamatangi is another who could be in the picture to ultimately replace his club teammate.
Fittler also confirmed that Ryan Papenhuyzen was well in contention for an Origin spot before injuring his hamstring and knee on the weekend against the Dragons.
“It’s heartbreaking for him. ‘Paps’ was right in the discussion - you could not look past him because he was playing so well,” Fittler said.
Fittler will name his team for Origin 1 following the completion of Round 12 in the NRL.